Method of and apparatus for slitting articles



METHOD OF AND APPARATUS FOR SLITTING ARTICLES Filed NOV. 8, 1947' Se t. 2, 1952 v. A. RAYBURN 2 SHEETSSHEET l INVENTOR MA. RA YBURN A 7' Tom/E y V. A. RAYBURN METHOD OF AND APPARATUS FOR SLITTING ARTICLES Filed NOV. 8, 1947 7 Sept. 2, 1952 2 SHEETS-SHEET 2 \A o g A 7' TORNE V INVENTOR VA. RA YBURN IJ IIIIII ll.

Patented Sept. 2, 1952 Maison OF AND APPARATUS Foesurmis ARTICLES H Vincent A. Rayburn, Baltimore, Md., assignor to Westernf Electric Company, Incorporated, New Xorlg, N.- Y, a, corporation of- New York- Applieationldoveuiber 8, 1947, Serial N 0.1784359 This invention relates to methodsoi' and ape paratus for slitting articles, and more partic: ularly to apparatus for continuously slitting strips-of material to for-m ribbons thereof.

' in processinguncured compounds including rubber ora synthetic rubber-like material for some manufacturing operations, a mass of such compound is rolled into a strip, and the strip is slit-longitudinally thereof to. form a. plurality of ribbons. Apparatus hitherto known has been incapable of satisfactorilys-litting suchstri s, f uncured. compound continuously and has. I? quired cutting elementsof a type requiring frequent sharpening to. maintain the; apparatus 11: operative condition.

object of the invention s impro se new and improved methQdsbii and a para us f r slitting articles.

.A method illustratin erta n. feature of t invention may nclu e torms aheetof material; to par ially mtm bbon herefrom, a twi tin ach ar ia ly rmed b n to tea the. ribbons part 7 an. ppar tu llustrating er ai ature of th invention may include means forscoring a e etioi n aterial to partially form ribbons theredent, and means for twisting Teach partially fosnsdribbon of a sheet scored'by the sheetsc orinjg means to tear the ribbonsapart A complete understanding of the invention may be o tain d f m. t f ll i g. de ai d d sbriptin of a method and an apparatus forrnns s ec fic embodim t he o when ead n comu' tion h he nded. drawi s, n which;

Fig. '1 is afraginientary'top plan view 'of'an apparatus forming one embodimentjof the 'lllygl' tion; 1

2 is a vertical section taken'alcng line 2-2 of 1. r

3- is a fragmentary, vertical-section taken along lines-30f 2, and

:6; Claims, (Cl. 164845-) Fig; i is *an enlarged, fragmentary vertical section taken along line 4-4-of Fig. 2.

Referring new in "detail to the drawings,- a wide strip H; (Fig. 1 which may be composed of unviilcanized, vulcanizable material, such as a compound includingrubber ora synthetic r-uo ber like material, or which may be composed of a thermoplastic compound or other, non plasticmaterial, is advancedto the right, as viewed ir Fig. 2-, by a pair of feed rolls 2-12, a pair'ofgroovin'gfrolls l"4";'and l5, of whi'chthe roll I! is aknife roll rand theroll -l 5-is 'an-anv1l rolL- and a p ain of separating rolls in and is spaced closely to the grooving rolls. iIbe :ieed

2 rolls l2-l2 are driven in opposite, inrunning directions at equal peripheral rates of speed by shafts 2B--2fi, and springs, of which a spring 22 is shown, urge the feed rolls l2'-l2- together so that the feed rolls grip the strip l0 firmly.

The knife roll l4, includes annular grooving knives 2424 provided with blunt cutting edges 26-26 projecting from a cylindrical portion 27 thereof. The knife roll M is rotated'ina counterclockwise direction, as viewed in Fig. 2, by a shaft 36 at such a rate that the peripheral speed of the cylindrical portion 21 thereof is about it} per cent higher than the peripheral speed of the-feed rolls [2-12. The shaft 30' is, mounted rotatably in slotted journal boxes "32 -32 (Fig. 1) which areslidable in guideways' 34-34 formed in side frame members St-36. Compression springs, of which a spring 38 is shown, urge the journal boxes 32-42 downwardly, asviewed in Fig. 2, toward the "anvil roll 15, which" is-rotated by a shaft 49 at such a rate that its peripheral speed is the same as that of the body portion 2?- of the knife roll l4 so that the portions the strip Ill between the feed rolls I2-l2 and the grooving rolls l4 and I'5- is tensioned longitudinally. The shaft 48 is mounted rotatablyin fixed journal boxes, of which a journal box 42 is shown. The springs illustrated by the spring 33 press the knife roll M toward the anvil roll f5 so that the knives 2 4-24 reduce the strip l il'to thin membranes 5U5fl (Fig. 3) connecting ribbons 52-52.

In practice, it has been found-that even very sharp-knives do not completely slit strips of un cured compound, such as the-strip Hi. The-anvil roll ['5 is rotated by the shaft in aclockwise direction at a peripheral rate of speed a sub stantial, predetermined amount slower than: that of the blunt edges 26-46 ofthe knives 2'4.-Z4 since-the'peripheral speed of the cylindrical pors tion 21- of the knife roll I4. is the same as that of the roll l5 and the knives project. :beyondthe cylindrical portion. The clilferential speeds of the knife edges and the anvil roll produce; for.- ward rubbing action by blunt knife edges which stresses the membranesbeyond .theyelastic limit thereof, and setsthe mem r ne. sathat the strip does. not return to. its; original section due to. resiliency after release.

As; the ribbons 52.--5-. 'QQ I 6 $dby" the me branes 56-50 are formed, they are advanced from the rolls I4 and T5 to the separating rolls l8 and I9, which are :r-otated opposite, ;in-

3 and the roll I9 is provided with a plurality of frustoconical sections 64-64 complementary to the sections 62-62. The sections 62-62 point to the right, as viewed in Fig. 4, and the sections 64-64 point in the opposite direction. Each of the sections 62-62 and 64-64 has the same length, which is the same as the distance between eachadjacent pair of knives 24-24 (Fig. 3), and each one of the sections 62-62 is directly over one of the sections 64-64. Each transversely aligned pair of the sections 62-62 and 64-64 is transversely aligned with one of the portions of the knife roll I4 between adjacent knives 24-24.

The shaft 58 is mounted rctatably in slotted journal boxes 68-68 (Fig. 1 mounted slidably in guideways (6-16 formed in side frame members 12-12. Compression springs, of which a compression spring 74 (Fig. 2) is shown, urge the journal boxes downwardly, as viewed in Fig. 2, toward fixed journal boxes, of which a jour nal box I6 is shown. The roll I8 is thereby urged toward the roll I9 to grip the ribbons 52-52 therebetween.

A compression spring i6 urges the roll I8 to the left, as viewed in Fig. 1, and a compression spring 19 (Fig. 2) urges the roll 6 to the right, as viewed in Fig. 1. The compression springs I8 and I9 maintain acute cutting edges 82-82 and 84-84 of the rolls I8 and I9 in contact and keep the sections 62-62 of the roll i8 in transverse alignment with the sections 64-64 of the roll I9.

As the strip I6 is pulled by the separating rolls I8 and I9 to the right, as viewed in Fig. 2, each of the ribbons 52-52 is twisted by the sections 62-62 and 64-64 so that its right hand edge 96, as seen in Fig. 4, is lifted and its left hand edge 92 is pushed down. This twisting of the ribbons 52-52 effects a tearing action on the thin membranes 56-56 (Fig. 3), and the acute cutting edges 82-82 and 84-84 of the separating rolls I8 and I9, respectively, together with the tearing action resulting from the twisting of the ribbons, sever the membranes 56-56 to completely separatethe ribbons 52-52. The separating rolls I8 and I9 are driven at such a rate of speed that they tend to advance the ribbons 52-52 at a speed somewhat greater than the rate at which the grooving rolls I4 and I5 deliver the ribbons so that the portions of the ribbons between these sets of rolls are tensioned longitudinally, which facilitates the transverse tearing action.

yThe difference in diameter in each of the frustoconical sections 62-62 and 64-64 between the cutting edge thereof and a portion 98 thereof, which is the smallest portion thereof,

preferably should be sufiicient to provide a twist to the ribbons 52-52 capable of tearing the membranes 56-56. In the design of the rolls I8 and I9, this difference is affected by the spacing between the central plane of the slitting rolls I4 and I5 and that of the separating rolls I8 and I9; i. e. the closer the set of separating rolls is to the set of grooving rolls, the less need be the angle'through which each strip is twisted from the grooving rolls to the separating rolls to maintain the necessary degree of twisting per unit of length of the ribbons. Preferably these two sets of rolls are kept as close together as possible.

Operation In the operation of the apparatus described hereinabove, the strip I6 is advanced from the feed rolls I2-I2 to the grooving rolls I4 and I5 and is tensioned therebetween. The grooving rolls l4 and I5 reduce the strip along equally spaced, longitudinal parallel lines to the thin membranes 56-56 (Fig. 3) to partially form the ribbons 52-52. The separating rolls twist the ribbons to tear the membranes apart to complete the forming of the ribbons, which the separating rolls convey from the grooving rolls. Twisting the ribbons tends to pull apart the edges 96-96 thereof, in edgewise directions so that the webs are tensioned laterally in a horizontal plane, as viewed in Fig. 3, in which they lie. This lateral tensioning plus the longitudinal tensioning of the webs from the differential speeds of the sets of grooving rolls and separating rolls facilitates the rupture of the membranes as adjacent edges of the ribbon are moved facewise apart.

The twist imparted to the ribbons is accentuated by differential tensioning of different portions of each ribbon imparted to the ribbons by the grooving rolls I4 and I5 and the separating rolls I8 and I9. The larger portions of each of the frustoconical sections 62-62 and 64-64 tend to advance the portions of the ribbons 52-52 which they contact at a greater rate of speed than that at which the smaller portions of these sections tend to advance the portions of the ribbons contacted thereby. Hence, the portions of each of the ribbons between. the grooving rolls and the separating rolls at the upper right hand and lower left hand corners of the ribbon are tensioned more than the portions thereof at the lower right handy and upper left hand corners thereof. This tends to twist each ribbon in a clockwise direction, thereby accentuating the twist imparted by the inclination'of the contacting surfaces of the frustoconical sections 62-62 and 64-64. C

Since the lower left hand portions of the ribbons 52-52, as viewed'in Fig.4, are tensioned more than the lower right hand corners, the membranes 56-56 are subjected to a tearing action. This aids the tearing action resulting from the twisting of the strips and the shearing action effected by the edges 82-82 and 84-84, which latter shearing action occurs if the membranes are not severed when they reach thebites of the edges 82-82 and 84-84. The above-described tearing and shearing actions insure severance of the membranes. 7

The above-described methods and apparatus serve to slit the strip I6 neatly and effectively. The apparatus is relatively light in construction as compared with apparatus heretofore known, and requires a minimum ofmaintenance to keep it in excellent shearing condition.

What is claimed is: 1

1. The method of slitting strips of tough, re-' silient plastic material, which comprises advancing such a strip longitudinally along a predetermined path, grooving the strip longitudinally along a plurality of parallel lines at a predetermined point in said path to form a plurality of partially severed ribbons, turning all of said ribbons in the same direction about their longitudinal axes at another point in said path to exert lateral tension on the grooved portions of the strip, longitudinally tensioning the portion of said strip between said points, and severing the portions of the strip connecting said ribbons while they are thus laterally and longitudinally tensioned to completely separate the ribbons.

2. The method of slitting thick strips of tough, resilient rubbery compounds, which comprises continuously advancing such a strip longitudi nally along a predetermined path, partially slitting the strip longitudinally along a plurality of parallel lines at one point in said path to form a plurality of partially severed ribbons separated by thin membranea'turning each of said ribbons in the same direction about its longitudinal axis at another point in said path to tension said membranes laterally, longitudinally tensioning the portion of said strip between said points, and severing the thin membranes while they are thus laterally and longitudinally tensioned to completely separate the ribbons.

3. Apparatus for slitting tough, resilient plastic material, which comprises means for continuously scoring a strip of such material longitudinally along a plurality of parallel lines to partially divide the strip into a plurality of ribbons, a pair of coacting twisting and shearing rolls positioned near and aligned with the strip-scoring means, each of said rolls being provided with a continuone series of frustoconical sections having sharp edges with the frustoconical sections of one of the rolls facing in one direction and the frustoconical sections of the other roll facing in the opposite direction, and means for rotating the rolls to advance a strip from the strip-scoring means and to tension and shear the strip along the lines dividing the ribbons.

4. Apparatus for slitting tough, resilient rubbery compounds, which comprises means for continuously scoring a strip of such material longitudinally along a plurality of parallel lines to divide the strip into a plurality of partially formed ribbons, a pair of parallel cutting and shearing rolls provided with a plurality of matched pairs of frustoconical sections having sharp edges, each of said pairs of frustoconical sections serving to engage and twist one of the partially formed ribbons and thereby laterally tension the adjacent scored portion of the strip while the sharp edges of the sections sever the strip along the scored portions whereby the ribbons are completely separated, and means for rotating the rolls to advance the strip therebetween and to tension the strip longitudinally to assist the severing action of the rolls.

5. Apparatus for slitting thick strips of tough, resilient rubbery compounds, which comprises means positioned at a predetermined point for continuously scoring a strip of such material longitudinally along a plurality of parallel lines to divide the strip into a plurality of partially formed ribbons separated by thin membranes, a pair of parallel twisting and shearing rolls provided with a plurality of matched pairs of frustoconical sections having sharp engaging edges, each of said pairs of frustoconical sections serving to engage and twist one of the ribbons and to thereby laterally tension the adjacent membrane while the sharp edges of said sections sever the membranes whereby the ribbons are completely separated, and means for rotating the rolls to advance the strip therebetween at such a rate of speed as to longitudinally tension the portion of the strip between the strip-scoring means and the cutting and shearing rolls and thereby assist the severing action of the rolls.

6. Apparatus for slitting thick strips of tough, resilient rubbery compounds, which comprises a pair of slitting rolls for partially slitting a strip of such material longitudinally along a plurality of parallel lines into a plurality of partially formed ribbons separated by thin membranes, means for rotating the slitting rolls so as to advance the strip therepast at a predetermined rate of speed, a pair of parallel twisting and shearing rolls provided with a plurality of matched pairs of frustoconical sections having sharp edges which edges are aligned with the thin membranes of a strip advancing therepast, each of said pairs of frustoconical sections serving to engage and twist one of the ribbons and to thereby laterally tension the adjacent membrane while said sections sever the membranes whereby the ribbons are completely separated, and means for rotating the twisting and shearing rolls at such a rate that they tend to advance the strip faster than do the slitting rolls whereby the strip is tensioned longitudinally and the severing action of the twisting and severing rolls is augmented.

VINCENT A. RAYBUEN.

EEFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

